To upgrade it you must right-click your Runite Bandosian Token and click, Check Contribution or re-equip it.

Bandosian tokens give:

A small bonus to divine energy

An increase to building construction/tear down rate by a small amount

Damage reduction from opposing forces by a small amount

Resistance to opposing player(s) interference

It can also be used to teleport to the Bandosian camp, southeast of Goblin Village, 10 times a day, even after the event. It is useful for accessing the Goblin Village for several quests, as well as the Captured Temple for its Wine of Zamorak spawn.